Soft, edible filling compositions for baked goods such as sandwich cookies are well known. Conventionally, such fillings are comprised of a hydrogenated fat or blends of fats, sugar, emulsifier and flavor.
In prior U.S. Pat. No. 3,244,536 to Kidger, it is stated that an essential requirement of a good shortening for a filler composition is that the shortening have a wide temperature range over which the fat is soft and workable, and yet in a solid state. This is necessary to give richness and tenderness to the finished product at room temperature, for instance about 70.degree. F., but also to provide a desired degree of hardness at an elevated hot day temperature of about 90.degree. F., to resist flow from the cookie either by gravity or when compressed by biting on the cookies.
In the '536 patent, specifications given for the fat composition are a Solids Fat Index (SFI) at 50.degree. F. of about 45%, at 80.degree. F. of at least about 25%, at 92.degree. F. of at least about 12.5%, and at 100.degree. F., not greater than 3%. At 104.degree. F., the solids content should not be greater than 0.5%.
It is stated in the patent that from the above figures it should be apparent that a good filler fat retains its consistency at room or ambient temperature and melts completely and rapidly at body temperature.
Another requirement of the fat composition is that it have good shelf stability even under hot weather conditions; that is, resistance to oxidation or oxygen degradation. An indication of the oxidative stability of an oil is the number of hours needed for an oil to obtain a peroxide value of 100 under standard conditions, known as the Active Oxygen Method or AOM Stability.
In the practice of the '536 patent, it is proposed to blend a partially hydrogenated fat having a high C.sub.18 fatty acid content (at least about 50%) with a vegetable oil having a high proportion of lauric acid, and then subject the blend to interesterification. Tallow and lard are indicated to be preferred partially hydrogenated fats. Coconut oil and palm kernel oil are listed as suitable high lauric vegetable oils. The end product is said to have a Wiley Melting Point between about 102.degree. and 108.degree. F., preferably between 102.degree. and 104.degree. F.
One problem with the composition of the '536 patent is that, in order to get the specified solids at 80.degree. F. and 92.degree. F., namely 25 and 12.5%, respectively, it is necessary to carry out the hydrogenation of the tallow or lard to a substantial extent. For instance, it is indicated in the patent that the hydrogenation of tallow is conducted to an Iodine Value of about 25-42. In the case of lard, the hydrogenation is conducted to an Iodine Value of about 41-49. In either event, the hydrogenation is sufficient so that at temperatures above 98.5.degree. F., or body temperature, there is substantial unmelted solids in the composition, leaving what is called a "tail" giving a slightly greasy sensation in the mouth following consumption of the cookie and filling.
In prior U.S. Pat. No. 4,214,012 to Ainger et al, a somewhat similar approach is taken to provide a biscuit cream filling. In this patent, the fat composition is an interesterified blend of a lauric component and a non-lauric component. In an example, an oleine fraction of palm kernel oil, remaining after removal of stearine by fractionation, having an Iodine Value of 15-25, is interesterified with a non-lauric stearine recovered from acetone fractionation of palm oil. The product obtained is one having a slip melting point range between about 28.degree.-40.degree. C. and a dilatation drop of at least about 500 over the last 10.degree. C. below slip melting point. As with the Kidger U.S. Pat. No. 3,244,536, there is no disclosure in this patent concerning the solids remaining, the so-called "tail", following melting of the fat at body temperature, and elimination of whatever slightly greasy sensation that might exist.
It is a principal object of the present invention to overcome the disadvantages of the prior art, and in particular to provide a fat system having an SFI configuration which provides good stand-up through a wide temperature range, but at the same time has at body temperature of 98.5.degree. essentially a zero solids content, or at least a solids content less than a perceptible amount. It is also an object of the present invention to provide a filling composition similar to that of the Kidger patent, but without the so-called "tail". The disclosure of the Kidger patent is incorporated by reference herein.